Seismic restraint of ceilings

ABSTRACT

A seismic restraint system for suspended ceilings has longitudinal ceiling perimeter restraint members each having a longitudinal web, a longitudinal bottom flange extending orthogonally from the web, integrally formed fixed connection apertures and floating connection slots orthogonally orientated with respect to the web. In use a pair of ceiling perimeter restraint members are installed horizontally at opposite sides of a suspended ceiling which has a grid of intersecting structural rails. Each ceiling perimeter restraint member is installed with the web attached to a respective adjacent structure with the bottom flange thereof extending away therefrom and with respective ends of the structural rails resting thereatop. Each structural rail running longitudinally between the ceiling perimeter restraint members is fixed in place at one end using at least one of the fixed connection apertures and slidably affixed at an opposite end using at least one of the floating connection slots.

FIELD OF THE INVENTION

This invention relates generally to arrangements for restraining building elements from perimeter supporting structures. More particularly, this invention relates to methods and components for seismically restraining suspended ceilings from perimeter walls, bulkheads or the like.

BACKGROUND OF THE INVENTION

Ceilings are typically made from a suspended metal grid of intersecting structural rails, wherein ceiling panels or tiles are laid in or fastened to the grid.

The ceiling grid may run on a single plane with mechanically interlocking rails (e.g. interlocking T-rails) or may be installed on two different levels with a mechanical device connecting the intersecting rails, such as wherein lower furring channels are connected to orthogonal top cross rails with locking keys.

These ceilings may be seismically restrained by connecting their perimeter to an abutting structure, such as a wall or bulkhead. According to this method, horizontal seismic actions within the ceiling system are transferred to the perimeter structure.

‘Perimeter restraint’ requires that every primary and secondary grid member shall have one end fixed (to provide seismic restraint) and the other end floating (to provide seismic isolation) at the perimeter.

As is shown in FIGS. 1 and 2 , normal practice is for the ceiling to be fixed on two adjacent sides and floating on the opposing two adjacent sides.

For flush-grid ceilings (e.g. ceilings comprising intersecting T-rails), the seismic load path along the grid members is provided by the mechanically interlocking rail connections. Current industry practice involves the use of proprietary perimeter seismic clips 129 as is illustrated in FIG. 3 , that allow for either a fixed or floating connection at either end of each grid member.

At the fixed end 121, seismic loads within the ceiling system are transferred to the perimeter supporting structure via the axial stiffness of grid members. At the floating end 120, the ceiling system is seismically isolated from the perimeter structure to avoid unwanted load swaps, as required. Seismic clips prevent the spreading of grid ends and provide stability at ceiling perimeters. Also, seismic clips prevent grid ends from sliding off at the edges. These clips are connected discretely at each terminal end of each grid member. When connecting to a cavity wall (e.g. dry-wall), an additional noggin member 130 is required to be installed within the wall cavity, to provide fixing support for the perimeter clips. This imposes additional labour and material cost and effort.

For the case of ceiling grids having over-crossing rails (e.g. ceilings comprising lower furring channel and orthogonal top cross rail-type grids), the intersections 131 between the upper and lower grid members must be restrained by additional means, as conventional devices such as locking keys are typically designed to provide gravity support only, not lateral restraint.

Failing to restrain grid intersections may result in sliding between intersecting grid members under horizontal loads, which defeats the purpose of seismic restraint, or may result in disengagement of the lower furring channel from the top cross rail and subsequent progressive collapse of the entire ceiling, a phenomenon commonly known as ‘blanket collapse’ which compromises life safety and may result in catastrophic fatalities. Provision for such intersection restraint incurs additional labour and material cost and effort.

It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.

SUMMARY OF THE DISCLOSURE

There is provided herein a continuous ceiling perimeter restraint member that acts as both a perimeter trim and a connector for either fixed or floating connections, without requiring additional structural support/backing such as noggins.

For T-rail ceilings, the use of a continuous track rather than discrete clips reduces the number of fasteners required to connect to the perimeter structure. As such, in effect, the perimeter trim, seismic clips, and supporting noggin are integrated into a single, continuous, face-fixed member, saving time and money.

As such, the continuous ceiling perimeter restraint member having integrated connectors allows for fixed or floating connections at the terminal ends of ceiling grid members and which does not require additional support noggins.

For ceilings having top cross rails crossing over furring channels, the ceiling perimeter restraint member provides lateral restraint in both orthogonal directions in the ceiling plane, without the need for lateral restraint at grid intersections.

In essence, the ceiling is restrained in both orthogonal directions only by the lower furring channels, whilst maintaining floating sides, as required. Seismic loads within the ceiling system are transferred to the perimeter structure via the axial, flexural and shear stiffnesses of the furring channels.

As such, the present method of perimeter restraint of ceilings with over-crossing two-way grids eliminates the requirement for additional horizontal restraint at ceiling grid intersections.

Furthermore, the present arrangement provides restraint in both orthogonal directions by the lower furring channel, without relying on the top cross rail, saving time and money.

This arrangement is particularly suitable for restraining ceilings in long corridors, which is generally challenging to achieve by conventional perimeter restraint methods, as the length at which the ceiling can be restrained is limited by the connection capacity at the adjoining wall at the corridor end, whereas according to the present method, a finite seismic mass is attributed to a single furring channel which can be repeated along the length of the corridor, virtually without limitation.

The fixed connection apertures and floating connection slots may provide both floating and fixed connections and may be on both flanges of the track. Furthermore, the unequally sized flanges allow the bottom flange to provide ledge support for the grid, making grid installation easier, and the upwardly-inclined edge of the upper flange prevents the grid member from jamming when sliding back and forth under seismic excitation.

Other ceiling types may be restrained similarly.

According to one aspect, there is provided a seismic restraint system for suspended ceilings, the system comprising longitudinal ceiling perimeter restraint members each having a longitudinal web, a longitudinal bottom flange extending orthogonally from the web, integrally formed fixed connection apertures and floating connection slots orthogonally orientated with respect to the web wherein, in use, a pair of ceiling perimeter restraint members are installed horizontally at opposite sides of a suspended ceiling, the suspended ceiling comprising a grid of intersecting structural rails, each ceiling perimeter restraint member installed with the web attached to a respective adjacent structure with the bottom flange thereof extending away therefrom and with respective ends of the structural rails resting thereatop, wherein each structural rail running longitudinally between the ceiling perimeter restraint members is fixed in place at one end using at least one of the fixed connection apertures and slidably affixed at an opposite end using at least one of the floating connection slots.

The ceiling perimeter restraint member may be installed without additional noggin support therebehind.

Each ceiling perimeter restraint member may further comprise a longitudinal upper flange at an opposite side of the web from the bottom flange and extending orthogonally from the web to the same side as the bottom flange.

The bottom flange may extend beyond the upper flange.

The upper flange may comprises a lip inclined away from the bottom flange.

The upper flange and bottom flange may be spaced apart according to the height of a structural rail such that an end of the structural rail wedges therebetween.

Each ceiling perimeter restraint member may comprise a plurality of punched out tabs, each being orthogonal with respect to the web and the bottom flange.

Each tab may have an outer edge extending beyond the bottom flange from the web.

Each tab may have a respective floating connection slot therealong and at least one fixed connection aperture adjacent to the floating connection slot.

Each tab may comprise a pair of fixed connection apertures.

The pair of fixed connection apertures may locate respectively adjacent to either end of the floating connection slot.

The structural rails may be a flush grid of T-rails and wherein webs thereof are connected to respective fixed connection apertures and floating connection slots.

The bottom flange may have the integrally formed fixed connection apertures and floating connection slots formed therethrough.

The bottom flange may comprise an alternating pattern of at least one fixed connection aperture and floating connection slots.

The bottom flange may comprise a pair of fixed connection apertures between adjacent floating connection slots.

The pattern may be an equidistant pattern.

The structural rails may comprise top cross rails crossing over furring channels and wherein webs of the furring channels are connected to respective fixed connection apertures and floating connection slots.

At least one furring channel may be fixed in place at one end using at least one of the fixed connection apertures and slidably affixed at an opposite end using at least one of the floating connection slots.

Opposite ends of the top cross rails may be left floating away from respective adjacent structures.

According to another aspect, there is provided a longitudinal ceiling perimeter restraint member for seismic restraint of ceilings having a web and an orthogonal bottom flange and integrally formed fixed connection apertures and floating connection slots orthogonally orientated with respect to the web.

The ceiling perimeter restraint member may further comprise a longitudinal upper flange at an opposite side of the web from the bottom flange and extending orthogonally from the web to the same side as the bottom flange.

The upper flange and bottom flange may be spaced apart according to the height of a structural rail such that an end of the structural rail wedges therebetween.

The ceiling perimeter restraint member may further comprise a plurality of punched out tabs, each being orthogonal with respect to the web and the bottom flange and wherein each tab has a respective floating connection slot therealong and at least one fixed connection aperture adjacent to the floating connection slot.

The bottom flange may have the integrally formed fixed connection apertures and floating connection slots formed therethrough.

According to another aspect, there is provided a method of restraining a ceiling comprising top cross rails crossing over furring channels, the method comprising forming a fixed connection to an adjacent structure at one end of at least one furring channel thereof and a laterally-restrained floating connection to a respective adjacent structure at an opposite end thereof and leaving ends of the respective top cross rails spaced away from respective adjacent structures.

Other aspects of the invention are also disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 shows a plan view of a seismically restrained ceiling in accordance with the prior art;

FIG. 2 shows a cross-sectional elevation view of the seismically restrained ceiling of FIG. 1 ;

FIG. 3 is a perspective view of ceiling perimeter seismic restraint in accordance with the prior art;

FIG. 4 shows a plan view of a seismically restrained ceiling in accordance with the prior art;

FIG. 5 shows an arrangement of a top cross rail crossing over a lower furring channel and seismically restrained with proprietary connectors in accordance with the prior art;

FIG. 6 shows a perspective view of a ceiling perimeter restraint member in accordance with a first embodiment;

FIG. 7 shows a front elevation view of the restraint member of FIG. 6 ;

FIG. 8 shows a top plan view of the restraint member of FIG. 6 ;

FIG. 9 shows a method of restraining a ceiling with a floating connection using the restraint member of FIG. 6 ;

FIG. 10 shows an elevation view of a floating connection formed using the restraint member of FIG. 6 ;

FIG. 11 shows an elevation view of a fixed connection formed using the restraint member of FIG. 6 ;

FIG. 12 shows a T-rail-type ceiling seismically restrained using restraint members of FIG. 6 ;

FIG. 13 shows a method of seismically restraining a ceiling comprising lower furring channels and top cross rails in accordance with an embodiment;

FIG. 14 shows a perspective view of a ceiling perimeter restraint member in accordance with a second embodiment;

FIG. 15 shows an end elevation view of the restraint member of FIG. 14 ;

FIG. 16 shows a top plan view of the restraint member of FIG. 14 ;

FIG. 17 shows a bottom plan view of the restraint member of FIG. 14 ;

FIG. 18 shows a perspective view of a floating connection formed using the restraint member of FIG. 14 ;

FIG. 19 shows a perspective view of a fixed connection formed using the restraint member of FIG. 14 ;

FIG. 20 shows a side elevation view of the floating connection of FIG. 18 ;

FIG. 21 shows a side elevation view of the fixed connection of FIG. 19 ;

FIGS. 22 and 23 show top cross rail floating connections; and

FIG. 24 shows a ceiling comprising furring channels and top cross rails seismically restrained using the restraint member of FIG. 14 .

DESCRIPTION OF EMBODIMENTS

A longitudinal ceiling perimeter restraint member 100 comprises a web 101 and a bottom flange 102 extending orthogonally from the web 101.

The restraint member 100 comprises integrally formed fixed connection apertures 103 and floating connection slots 104 orthogonally orientated with respect to the web 101. In the manner illustrated in FIGS. 12 and 24 , a pair of ceiling perimeter restraint members 100 are installed horizontally at opposite sides of a suspended ceiling 105.

The suspended ceiling 105 comprises a grid of intersecting structural rails 106 which may be suspended from ceiling wires 107 attached to adjustable ceiling clips 108 thereof.

Each ceiling perimeter restraint member 100 is installed with the web 101 thereof attached to a respective adjacent structure 109, such as a wall, bulkhead or the like, and with the bottom flange 102 thereof extending away from the structure 109. In the embodiment shown, the structure 109 is a dry-wall comprising face board 112 and vertical supportive wall studs 110 therebehind.

Each structural rail 106 running longitudinally between the ceiling perimeter restraint members 100 rests atop respective bottom flanges 102 at either end thereof.

Furthermore, each structural rail 106 running longitudinally between the ceiling perimeter restraint members 100 is fixed in place (i.e. a fixed perimeter connection) at one end using at least one of the fixed connection apertures 103 and slidably affixed (i.e. a floating perimeter connection) at an opposite end thereof using at least one of the floating connection slots 104.

As is illustrated in FIG. 9 , each perimeter restraint member 100 may be installed without additional noggin support therebehind. In this regard, for a dry-wall application as shown in FIG. 9 , fasteners 111 may attach the ceiling perimeter restraint member 100 through the face board 112 to a flange 113 of a wall stud 110 therebehind.

Each ceiling perimeter restraint member 100 may further comprise an upper flange 114 at an opposite side of the web 101 from the bottom flange 102 and extending orthogonally from the web 101 to the same side as a bottom flange 102.

The upper flange 114 may further comprise a lip 115 inclined away from the bottom flange 102. The upper flange 114 and the bottom flange 102 may be spaced apart to accommodate an end of a rail 106 therebetween whilst minimising vertical movement. In a preferred embodiment, the upper flange 114 and the bottom flange 102 are spaced apart according to the height of the rail 106 such that an end of the rail 106 wedges therebetween.

Furthermore, the bottom flange 102 may extend beyond the upper flange 114 and wherein the inclined lip 115 guides the top of the rail 106 in under the upper flange 114 whilst the bottom of the rail 106 slides across the bottom flange 102 orthogonally with respect to the web 101.

FIG. 12 shows an embodiment wherein the ceiling 105 comprises a flush grid of T-rails 106. As is shown in FIG. 9 , each T-rail 106 may comprise a metal sheet folded over to define a bulb 116, a web 117, and side flanges 118 extending orthogonally from either side of the bottom of the web 117.

FIGS. 6-12 show a ceiling perimeter restraint member 100 according to a first embodiment which is suited for T-rail-type ceilings 105. In accordance with this embodiment, the restraint member 100 comprises a plurality of punched out tabs 119, each being orthogonal with respect to both the web 101 and the bottom flange 102. As is illustrated in FIG. 8 , an outer edge of each tab 119 may extend beyond the bottom flange 102.

Each tab 119 may have a respective floating connection slot 104 therealong and at least one fixed connection aperture 103 adjacent to the floating connection slot 104. Each tab 119 may also comprise a pair of fixed connection apertures 103. Furthermore, the pair of fixed connection apertures 103 may locate respectively adjacent to either end of the floating connection slot 104.

Seismic ceiling restraint using the ceiling perimeter restraint member 100 of the first embodiment is illustrated in FIGS. 9-12 wherein ceiling perimeter restraint members 101 are affixed horizontally to adjacent structures 109 wherein, with particular reference to the dry-wall embodiment shown, fasteners 111 along the length of the web 101 thereof affix the web 101 directly to flanges 113 of vertical wall studs 110 through a face board 112 thereof.

As is illustrated in FIG. 10 , one side of each longitudinal T-rail 106 running between the oppositely affixed ceiling perimeter restraint members 100 may be affixed as a floating connection 120 wherein a fastener 122 affixes the web 117 of the T-rail 106 to a floating connection slot 104 of a tab 119. As is further illustrated in FIG. 10 , the spacing between the lower flange 102 and the upper flange 114 may be such that the T-rail 106 is wedged therebetween. In the embodiments, the spacing between the upper flange 114 and the lower flange 102 is slightly less than the height of the T-rail 106 such that the upper flange 114 bends upwardly slightly to accommodate the top of the T-rail 106 thereunder when guided therein by the inclined lip 115.

FIG. 11 illustrates a fixed connection 121 at an opposite end of the same T-rail 106 wherein fasteners 122 secure the web 117 of the T-rail 106 using the fixed connection apertures 103. In the embodiment shown, a pair of fasteners 122 are used for a respective pair of fixed connection apertures 103.

FIG. 12 shows the suspended ceiling 105 with the longitudinal T-rails 106 running between the oppositely affixed ceiling perimeter restraint members 100 having the floating connections 120 at one end and the fixed connections 121 at the opposite end. The suspended ceiling 105 may be secured wherein fixed connections 121 are provided at adjacent orthogonal sides whereas floating connections 120 are provided at opposite adjacent orthogonal sides.

FIGS. 13-24 show an embodiment wherein the suspended ceiling 105 comprises top cross rails 123 crossing over furring channels 124. FIGS. 14-17 show the ceiling perimeter restraint member 100 in accordance with a second embodiment suited for this type of ceiling arrangement.

In accordance with this embodiment, the bottom flange 102 has integrally formed fixed connection apertures 103 and floating connection slots 104 therethrough. In the embodiment shown, the bottom flange 102 comprises an alternating pattern of at least one fixed connection aperture 103 and floating connection slots 104.

The particular embodiment shown has a pair of fixed connection apertures 103 between adjacent floating connection slots 104. Furthermore, the alternating pattern may be an equidistant pattern.

FIGS. 18 and 20 show a floating connection 120 wherein the ceiling perimeter restraint member 100 is affixed to an adjacent structure 109 in the aforedescribed manner and wherein a fastener 126 goes in underneath the bottom flange 102 through a floating connection slot 104 and secures through a bottom web 125 of the furring channel 124.

FIGS. 19 and 21 show a fixed connection 121 at an opposite end of the furring channel 124 wherein at least one fastener 126 goes through the bottom flange 102 through a respective fixed connection aperture 103 thereof and which secures through the bottom web 125 of the furring channel 124.

As is also illustrated in FIGS. 18 and 19 , the spacing between the upper flange 114 and bottom flange 102 may wedge the furring channel 124 therebetween.

FIGS. 22 and 23 illustrate top cross rail floating connections 127 wherein the top cross rails 123 are left floating away from the adjacent structures 109.

Furthermore, with reference to FIG. 13 , there is shown a way to restrain a suspended ceiling comprising a gridwork of top cross rails 123 and lower furring channels 124 wherein the furring channels 124 are connected with the fixed connection 121 at one end and a laterally-restrained floating connection 128 at an opposite end thereof and wherein the top cross rails 123 have floating connections 127 at both ends thereof. The laterally-restrained floating connection 128 is so named because each furring channel 124 may slide relative to the restraint member 100 along the longitudinal axis of each furring channel 124 but wherein the ends of each furring channel 124 connected to the restraint member 100 at the laterally-restrained floating connection 128 are prevented from moving laterally with respect to the longitudinal axis of each furring channel 124 by the respective floating connection slot 104.

The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practise the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed as obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.

The term “approximately” or similar as used herein should be construed as being within 10% of the value stated unless otherwise indicated. 

1. A seismic restraint system for suspended ceilings, the system comprising longitudinal ceiling perimeter restraint members each having a longitudinal web, a longitudinal bottom flange extending orthogonally from the web, integrally formed fixed connection apertures and floating connection slots orthogonally orientated with respect to the web wherein, in use, a pair of ceiling perimeter restraint members are installed horizontally at opposite sides of a suspended ceiling, the suspended ceiling comprising a grid of intersecting structural rails, each ceiling perimeter restraint member installed with the web attached to a respective adjacent structure with the bottom flange thereof extending away therefrom and with respective ends of the structural rails resting thereatop, wherein each structural rail running longitudinally between the ceiling perimeter restraint members is fixed in place at one end using at least one of the fixed connection apertures and slidably affixed at an opposite end using at least one of the floating connection slots.
 2. The system as claimed in claim 1, wherein the ceiling perimeter restraint member is installed without additional nogging support therebehind.
 3. The system as claimed in claim 1, wherein each ceiling perimeter restraint member further comprises a longitudinal upper flange at an opposite side of the web from the bottom flange and extending orthogonally from the web to the same side as the bottom flange.
 4. The system as claimed in claim 3, wherein the bottom flange extends beyond the upper flange.
 5. The system as claimed in claim 3, wherein the upper flange comprises a lip inclined away from the bottom flange.
 6. The system as claimed in claim 3, wherein the upper flange and bottom flange are spaced apart according to the height of a structural rail such that an end of the structural rail wedges therebetween.
 7. The system as claimed in claim 1, wherein each ceiling perimeter restraint member comprises a plurality of punched out tabs, each being orthogonal with respect to the web and the bottom flange.
 8. The system as claimed in claim 7, wherein each tab has an outer edge extending beyond the bottom flange from the web.
 9. The system as claimed in claim 7, wherein each tab has a respective floating connection slot therealong and at least one fixed connection aperture adjacent to the floating connection slot.
 10. The system as claimed in claim 9, wherein each tab comprises a pair of fixed connection apertures.
 11. The system as claimed in claim 10, wherein the pair of fixed connection apertures locate respectively adjacent to either end of the floating connection slot.
 12. The system as claimed in claim 7, wherein the structural rails are a flush grid of T-rails and wherein webs thereof are connected to respective fixed connection apertures and floating connection slots.
 13. The system as claimed in claim 1, wherein the bottom flange has the integrally formed fixed connection apertures and floating connection slots formed therethrough.
 14. The system as claimed in claim 13, wherein the bottom flange comprises an alternating pattern of at least one fixed connection aperture and floating connection slots.
 15. The system as claimed in claim 14, wherein the bottom flange comprises a pair of fixed connection apertures between adjacent floating connection slots.
 16. The system as claimed in claim 14, wherein the pattern is an equidistant pattern.
 17. The system as claimed in claim 13, wherein the structural rails comprise top cross rails crossing over furring channels and wherein webs of the furring channels are connected to respective fixed connection apertures and floating connection slots.
 18. The system as claimed in claim 17, wherein at least one furring channel is fixed in place at one end using at least one of the fixed connection apertures and slidably affixed at an opposite end using at least one of the floating connection slots.
 19. The system as claimed in claim 18, wherein opposite ends of the top cross rails are left floating away from respective adjacent structures.
 20. A longitudinal ceiling perimeter restraint member for seismic restraint of ceilings having a web and an orthogonal bottom flange and integrally formed fixed connection apertures and floating connection slots orthogonally orientated with respect to the web.
 21. The ceiling perimeter restraint member as claimed in claim 20, further comprising a longitudinal upper flange at an opposite side of the web from the bottom flange and extending orthogonally from the web to the same side as the bottom flange.
 22. The ceiling perimeter restraint member as claimed in claim 21, wherein the upper flange and bottom flange are spaced apart according to the height of a structural rail such that an end of the structural rail wedges therebetween.
 23. The ceiling perimeter restraint member as claimed in claim 20, further comprising a plurality of punched out tabs, each being orthogonal with respect to the web and the bottom flange and wherein each tab has a respective floating connection slot therealong and at least one fixed connection aperture adjacent to the floating connection slot.
 24. The ceiling perimeter restraint member as claimed in claim 20, wherein the bottom flange has the integrally formed fixed connection apertures and floating connection slots formed therethrough.
 25. A method of restraining a ceiling comprising top cross rails crossing over furring channels, the method comprising forming a fixed connection to an adjacent structure at one end of at least one furring channel thereof and a laterally-restrained floating connection to a respective adjacent structure at an opposite end thereof using respective longitudinal ceiling perimeter restraint members, each having a longitudinal web, a longitudinal bottom flange extending orthogonally from the web, integrally formed fixed connection apertures and floating connection slots orthogonally orientated with respect to the web, and leaving ends of the respective top cross rails spaced away from respective adjacent structures. 